SECTION II. THE DISTRIBUTION OF FER- 

 TILIZERS OVER ROTATIONS OF CROPS 



THE practice of growing crops in rotation has prevailed from 

 very ancient times, but it is only during the last two centuries 

 that the varied and extended rotations now familiar have 

 been extensively practised. In very primitive times the 

 forest dwellers burnt down a small portion of forest, sowed 

 grain on the ashes, and, after exhausting their little field in 

 the course of ten years, moved to another part of the forest 

 and repeated the process. The plot of ground which they had 

 left, as being no longer valuable to them, was quite well 

 suited for forest reproduction, and soon grew trees, so that 

 these primitive men of prehistoric times possessed a rotation 

 of ten years' grain and fifty years' scantling and small timber. 

 Of the more well-defined forms of rotation the oldest 

 known system was a simple two-course of grain and bare 

 fallow in alternate years. The Romans, however, had 

 instituted a three-course rotation of bare fallow, wheat and 

 beans, which the}' introduced into England with their con- 

 quest. Whilst in the British Isles this three-course rotation 

 appears to have been continued, no further progress was made 

 until the beginning of the eighteenth century, when Viscount 

 Townshend introduced the famous Norfolk four-course 

 rotation, which included in succession wheat, turnips, barley 

 and clover. From that time until now many new rotations, 

 varied to suit local conditions, have been established through- 

 out Great Britain. To obtain the largest amount of profit 

 and the greatest yields, with the least possible exhaustion 

 of the soil, are objects which every farmer has in view, and it 

 has become a well-established rule that under ordinary condi- 

 tions some system of rotation is the best method of obtaining 

 those ends. It is true, that at Rothamsted, many crops 

 have been grown continuously by the expenditure of much 



